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Sea Otter Savvy

Sea Otter Science And Community Outreach

Sea Otter Society: The Breakfast (Lunch, and Dinner) Club

sea otter society food

sea otter society food quarter lb 350

By Claire Mayer

What we eat turns to heat! Everyone has that one friend who lives to eat and not the other way around. The next meal is planned before the current is consumed. And while this is a choice for most humans it is not a choice for our friend the sea otter. Just to stay alive in these cold waters of the Pacific Ocean, sea otters must eat 25% of their body weight per day. If an 80 lb. sea otter ate only Quarter Pounders, he’d have to eat 80 of them every day! Can you imagine chowing down every day on three hearty breakfasts, four lunches, two dinners and then a midnight snack or two? While it may sound glorious to some it would surely require a lot of meal prep!  For sea otters the work is in the foraging ─ the finding and processing of prey.

Being the only marine mammal lacking a thick layer of blubber, sea otters rely on their high metabolism and dense fur to stay warm in a cold ocean. Because the calories they eat are converted to heat this helps maintain their high body temperature (roughly 100 degrees Fahrenheit). To generate the number of calories necessary to fuel the sea otter’s “heat engine” equates to one thing…eating, eating and more eating.

Sea otter biting into the anti-predator defense system of an urchinOuch! A sea otter biting into the anti-predator defense system of an urchin. Photo by Joan TisdaleWhat most don’t know is that finding so much food means very hard work for the sea otter. Not only is it extremely time consuming (in some parts of their range they may spend half of a 24-hour day foraging), but their various foods (aka prey items), have evolved an array of defenses to AVOID being eaten! For prey it pays to be difficult to locate and tough to open. Just what does the average sea otter go through to get a good day’s meal? Try dives to the bottom while holding their breath and kicking against the buoyancy of their fur’s air layer to dig for clams and worms, or patiently prying abalone and clumps of mussels from their rocks along the shore. An abalone meal may require 10 or more dives (and a rock tool) to pry loose. A sea otter can often be seen wrestling a prickly urchin or an angry crab aboard its chest while a stealthy gull stands by waiting for scraps. A sea otter specializing in small marine snails must stuff her underarm pockets full and pulverize each snail on a rock anvil. The struggle is real for the sea otter when it comes to finding food, but find food they must ─ just a few days without sufficient food can mean starvation. Not only does foraging take great effort, but their meal can pinch back (no thanks!) All this eating not only feeds the sea otter but keeps numbers of herbivores like urchins under control helping the kelp forest to thrive.

So the next time you see a sea otter devouring a tasty morsel be happy for the successful forage attempt. Maybe take a moment to appreciate all the hard work, time and energy that went into that dive, pry or dig in the sand. Be mindful too of the endless food choices within our arms' reach at the grocery store as compared to the limited options available to a sea otter foraging for their survivial or that of their offspring. Just as we don’t like our own precious mealtimes being interrupted let those sea otters dine in peace. As they finish that meal, they will already be thinking about the next! 

About guest blogger Claire Mayer: Claire was born and raised in Monterey, California. She is a former animal care volunteer with the Monterey Bay Aquarium's Sea Otter Research and Conservation program. She currently works as a Veterinary Assistant in Carmel, California. 

Read about the science of sea otter foraging:

Individual variation in prey selection by sea otters, 2003.pdf

Food limitation leads to behavioral diversification, 2008.pdf